A Simple Comb Filter

Since the pulses are equally spaced in time at an interval equal to the loop time $\tau = M/f_s$ seconds, it is periodic and will sound at the frequency $f_0 = 1/\tau$.

Figure 9: Impulse and magnitude response of a comb filter with feedback g = 0.8.

The comb filter is so called because its amplitude response resembles the teeth of a comb.

The spacing between the maxima of the ``teeth'' is equal to the natural frequency.